Write prose, run code, see results inline. Python, R, Julia, JavaScript, and Bash
in a single document. Real-time collaboration. Publish to the web with one action.
Your files stay as plain .md files.
Write markdown. Fence a code block. Run it. The output appears right below, in the same document. Variables persist across cells. Everything is saved as a plain text file you can version control, grep, and open in any editor.
Each code block declares its language. Run Python for data, R for statistics, Julia for simulation, Bash for system tasks, JavaScript for visualization -- all in the same file, with outputs inline.
CRDT-based editing. Multiple people work on the same document simultaneously. Cursor presence, no conflicts, works offline and merges on reconnect.
Hover a variable to see its value, not just its type. Autocomplete from the live runtime session. Inspect dataframes, preview plots, explore state.
One action turns a notebook into a published page. Share analysis, documentation, or interactive articles as a URL. No export step.
A unified design token system controls everything from syntax highlighting to widgets to the shell. Ship your own theme or use the built-in dark and light modes.
AI writes to the document the same way you do -- as a collaborator. It supports thinking and exploration without replacing the work.
No proprietary format. No JSON cell arrays. Your documents are .md files.
Version control, diff, grep, and open them anywhere.
The editor, runtimes, sync layer, and platform services are all open source. Build on top of them, self-host, or use the hosted version at markco.dev.